Our broad objective is to understand how various nutritional and hormonal factors govern the synthesis of fat in animals. We are particularly interested in the very rapid and large activation which we have observed almost immediately after mice ingest a fat-free, glucose-rich test-meal. (1) The significance of intermuscular fat in the synthesis and deposition of fat in mice; (2) the role of the liver and of plasma lipoprotein triglycerides in the conversion of dietary carbohydrate to depot fat in mice fed various diets; (3) the molecular basis of rapid lipogenic activation by dietary glucose; (4) a search for animal models that may be more suitable than rodents for the study of carbohydrate-induced hyperlipemia. Various C14-labeled precursors of triglyceride fatty acids will be used to carry out the in vivo kinetic studies in mice, rats, and pigs.